1. Field of the Invention
The present invention relates to a method of acquiring data from a multi-element detector in an infrared imaging apparatus, and more particularly to an improvement in a method of acquiring data from a multi-element detector in the case in which a Fourier transform infrared spectroscopic device of a continuous scan type is used.
2. Prior Art
A multi-element detector using an MCT or an InSb is referred to as a Focal Plane Array (FPA) detector, and has a mechanism for scanning a photoelectric output from each element arranged one-dimensionally or two-dimensionally and is utilized for a detecting device of an infrared imaging apparatus.
In an infrared imaging apparatus comprising a Fourier transform infrared spectroscopic (FTIR) device for detecting a signal by means of the FPA detector, a light incident from a light source of the FTIR device becomes interferogram by an interferometer and is irradiated onto a sample. The light transmitted through the sample is photoelectrically converted by an FPA detector and thus generates an analog electric signal. The analog electric signal is converted into a digital signal by an A/D converter and is then transmitted to a computer, and is stored as digital data in a memory. The data are subjected to an arithmetic processing by a CPU and an infrared image of the sample is then displayed on the display based on image data obtained finally.
By using a Fourier transform infrared spectroscopic (FTIR) device of a step scan type as an infrared imaging apparatus, for example, it is possible to scan all elements at an optional scanning speed in each step to obtain data.
In the infrared imaging apparatus comprising the FTIR device for detecting a signal by a multi-element detector, however, there is a problem in that the FTIR device of a step scan type is expensive. Consequently, it has been desired that a more inexpensive continuous scan type should be used. For this reason, it has been desirable to obtain a method of acquiring data from an FPA detector when an FTIR device system of a continuous scan type is applied.